Radiator cap



FIG. 1 is a top and side perspective view of a radiator cap showing my new design;

FIG. 2 is an enlarged top plan view thereof;

FIG. 3 is an enlarged side elevational view thereof, the opposite side being a mirror image of that shown;

FIG. 4 is an enlarged front elevational view thereof, the rear view being a mirror image of that shown; and

FIG. 5 is an enlarged bottom plan view thereof.

The radiator and spring shown in broken lines in the drawing are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a radiator cap, as shown and described. 